Study On Qo S Level Of Message Queuing Telemetry Transport Protocal Via Lyapunov Optimization

With the rapid development of mobile Internet and Internet of things technology,the lightweight,scalable and adaptable message telemetry transmission(MQTT)protocol based on the publish / subscribe model has been paid more and more attention.However,the server will suffer enormous pressure with the increasing amount of terminal devices.Under conditions of system stability,how to optimize the quality of service(QoS)of the message without increasing the cost of services has become an important research area.In view of the above research background,we proposed a mathematical model of the queueing system and then designed a self-adaptive algorithm which can guarantee the quality of the message service in a poor network environment with the Lyapunov optimization theory as the guidance and the MQTT protocol as the standard transmission protocol.The main work of this study show as follows:(1)Introducing the relative research of message push protocol and QoS level selection problem over MQTT protocol,and then the conception of two message queuing models is proposed.(2)According to Lyapunov theory,we proposed a stability model of the queuing system,and construct energy function to control the stability of the system.(3)Designing a strategy to dynamically adjust the QoS level on the basis of the conclusion of Lyapunov drift plus penalty function.(4)Building the experimental environment of the MQTT protocol message service quality optimization model.Then,contrasting the QoS optimization model proposed in this paper with traditional QoS selection method and verifying the usage scenario and superiority of ours.The experimental results show that when the network status between the client and the broker is not good or the message payload is large,the QoS optimization model proposed in this paper effectively improves the QoS level on the premise of ensuring the stability of the system.